The new upgrade, called LLMQ-based ChainLocks, makes the masternodes to lock new blocks, which prevents issues like double spends and network forks. After the upgrade, each successful block will become immutable the moment it is broadcasted, and its transactions become irreversible. Dash Core CMO, Fernando Gutierrez says that the new upgrade makes 51% attacks and reorgs unbearably expensive.
He added that measuring security in terms of hashing power doesn’t make sense, but the cost behind executing a successful attack does, and that’s what makes Dash a more secure blockchain than others. The combination of InstantSend Transactions and ChainLocks make settling Dash transactions in seconds possible, by allowing users to spend their coins soon after they receive them. This significant reduction in time and improvement in functionality will help expand adoption and push harder for new use cases. He further added,
By being able to instantly re-spend the funds that you receive, things like remittances can be done with seconds’ notice, which is unthinkable with other remittance methods.
ChainLock adds an additional layer of security to the network blocks. Dash Core CEO, Ryan Taylor commented,
It doesn’t matter if someone is mining a longer chain in secret in a 51% attack. Someone could have 99% of the network power, but if anyone else publishes their block first, the chain becomes invalid. This level of network consensus can be reached extremely quickly and reaches, I would argue, better than bitcoin security in four to six seconds.